Round baler with vertically oriented start chamber

ABSTRACT

A round baler includes front and rear expandable members arranged to form a vertically oriented start chamber which expands to a cylindrical shape during bale formation. An arm which supports the front expandable member is pivotally mounted and carries guide members at its ends around which the front expandable member passes. Upper and lower T-shaped supports which support the rear expandable member are pivotally mounted, and each T-shaped support carries a pair of guide members for engaging the rear expandable member.

BACKGROUND OF THE INVENTION

This invention relates to agricultural balers and more particularly toso-called round balers which produce cylindrical bales or rolls of cropmaterial.

In general, round balers are of two types: the expanding chamber typewhich produces bales with a relatively hard core and a generally highand relatively constant density throughout; and the fixed chamber typewhich produces bales with a relatively soft core but a relativelycompacted or hard outer layer or shell.

The advantages of expanding chamber balers are that they pack more cropmaterial into a bale compared with a similarly sized soft core bale, andthey can produce bales of any size up to the maximum which a givenmachine is capable of producing, with all sizes of bales being ingenerally good order from the standpoint of being subjected to handlingwithout falling apart. The advantages of fixed chamber balers are thatthey produce bales with a reduced tendency to molding if the cropmaterial is baled wet and the soft bale core presents no problems tocattle when feeding from the bale, whereas hard bale cores can bedifficult to tear apart. Fixed chamber balers produce with goodweathering characteristics due to the hard shell, which ensures a balewhich is very stable when being handled. Fixed chamber balers are ofrelatively simple design and they normally have no difficulty in forminga bale core which can sometimes be a problem with expanding chamberbalers when handling short lengths of crop material.

U.S. Pat. No. 4,182,101 discloses a round baler of the expanding chambertype which has a single endless web in the form of a series ofside-by-side belts extending around a plurality of rollers to define avertically disposed bale starting chamber. One of the rollers issupported by a pair of arms that are pivotally mounted to the side wallsof the baler. Springs are provided to normally urge the arms in adownward direction to maintain tension in the belts.

SUMMARY OF THE INVENTION

The present invention provides a round baler having a base frame, sidewalls attached to the base frame, and first and second expandablemembers arranged to define together with the side walls an initialgenerally vertically oriented wedge-shaped start chamber which expandsto a generally cylindrical shape during bale formation. An arm isprovided for supporting the first expandable member. The arm ispivotally mounted to at least one of the side walls and carries guidemembers at the ends thereof around which the first expandable memberpasses. Upper and lower T-shaped supports are provided to support thesecond expandable member. The T-shaped supports are pivotally mounted onat least one of the side walls and carry guide members for engaging thesecond expandable member. The arm is normally urged in a direction tomaintain tension in the first expandable member, and the T-shapedsupports are normally urged in opposite directions relative to eachother to maintain tension in the second expandable member.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1. is a schematic side view of a first embodiment of round balershowing the machine empty;

FIG. 2 is a view similar to that of FIG. 1 but showing the machine witha completed bale;

FIG. 3 is an enlarged view of a portion of FIG. 1;

FIG. 4 is a side view of FIG. 3;

FIG. 5 is a schematic view of a component of FIG. 1;

FIG. 6 is a partial sectional view, on the linve VI--VI of FIG. 5;

FIG. 7 is plan view of FIG. 6;

FIG. 8 is a sectional view on the line VIII--VIII of FIG. 7;

FIG. 9 is an enlarged view of a still further component of FIG. 1;

FIG. 10 is a partial sectional view on the line X--X 20 of FIG. 9;

FIG. 11 is an enlarged view of yet another position of FIG. 1;

FIG. 12 is a partial longitudinal section of the component of FIG. 11;

FIG. 13 is a view of an alternative component for the first emobdiment;and

FIGS. 14 and 15 are views similar to those of FIGS. 1 and 2,respectively, but showing a second embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 1 and 2, the first embodiment is in the form of apull-type round baler comprising a base frame 1 carrying a pair ofground engaging wheels 2 and having attached thereto a drawbar 3 forconnection to a tractor (not shown) or other towing vehicle. A driveshaft 4 extends above the drawbar 3 and is connected at one end to aninput shaft 5 of a gearbox 6, and connectable at the other end to apower-take-off shaft (also not shown) of the towing vehicle. Side walls7 of the machine are attached to the base frame 1, the side walls 7partially defining a bale forming chamber by providing the sidestherefor. The front and rear of the bale forming chamber are defined byportions of respective front and rear expandable members 8 and 9 which,when the machine is empty (FIG. 1) form together with the side walls 7 agenerally vertically oriented, wedge-shaped (as seen in side view) startchamber 11, and which expand on the formation of a bale to form acylindrical bale chamber shape 11' (FIG. 2). Each side wall 7 is split,with the front expandable member 8 forming a front portion of the balechamber in conjunction with one portion of each side wall 7, and therear expandable member 9 forming a rear portion of the bale chamber inconjunction with the other portion of each side wall 7.

As seen in FIGS. 1 and 2, the rear portion of the bale chamber is largerthan the front portion and is disposed in a tailgate 12 for the machinewhich is pivotable upwardly in order to effect discharge of a completedbale 13 (FIG. 2) from the machine. With this differential sizing of thefront and rear portions of the bale chamber, the center of gravity of acompleted bale lies within the rear portion of the bale chamber, wherebythere is a natural tendency for a completed bale to roll from themachine once the tailgate 12 has been raised, which tendency greatlyfacilitates bale discharge.

Pivotally mounted at the front of the machine is a conventional croppick-up unit 14 which, in use, picks up crop material from the groundand delivers it to a combined crop feeder and bale support device 15located at the bottom of the bale start chamber 11. Located within therear portion of the bale chamber and disposed at the front bottom cornerthereof adjacent the feeder and support device 15 is a rotor 16 whichextends between the side walls 7. The rotor 16 also helps to support abale during its formation.

Having described the overall machine in general, certain components willnow be described in greater detail with reference to FIGS. 3 to 12, inaddition to FIGS. 1 and 2, of the drawings. Looking first at the balechamber, the front expandable member 8 partially defining the front ofthe chamber comprises two transversely spaced apart endless chains 17each extending around a driven sprocket 18, an idler sprocket 19 and anon-toothed guide roller 21 disposed in a triangular arrangement as seenin side view in FIGS. 1 and 2. The chains 17 are disposed toward, butinset from the respective sides of the machine and are interconnected bya plurality of slats 22 which extend transversely of the machine, witheach end of each slat 22 extending past the associated chain 17 andterminating just short of the side walls 7 as seen in FIG. 5. Theconstruction of each slat 22 will be described hereinafter.

Referring to FIGS. 3 and 4, the sprocket 19 and guide roller 21associated with each chain 17 are mounted for rotation on an arm 23which in turn is pivotally mounted on the frame 1 via a pivot shaft 24which is common to both arms 23. The pivot shaft 24 is offset from thecenters of the arms 23 and is carried in bushings 25. It will be seenfrom FIG. 4 that each arm 23 comprises a pair of spaced members betweenwhich extend two spigots 26 on which the sprocket 19 and guide roller 21are respectively mounted via bearings 27, only the sprocket 19 beingshown in FIG. 4. The pivot shaft 24 has, at each end, a first portion ofreduced diameter around which is disposed a torsion spring 28, and asecond portion of further reduced diameter which is received by theassociated bushing 25. Each spring 28 serves to bias the associated arm23 in a clockwise direction as seen in FIGS. 1 and 2, whereby tension inthe chain 17 is maintained and any slack therein resulting from wear isautomatically taken up. The pivotal mounting of the arms 23 allows themto rotate as a bale is being formed as will be described.

This tensioning of each chain 17 is achieved by locating one end 29 ofeach spring 28 against a stop 31 fixed to the related arm 23, andlocating the other end 32 of each spring 28 against a stop 33 fixed toone end of an arm 34 located on the outside of the associated side wall7, the stop 33 extending through an arcuate slot 35 in the side wall 7.Each arm 34 is pivotally mounted on the pivot shaft 24 via theassociated bushing 25 and has a reinforcing flange 36 extending aroundits periphery and away from the side wall 7 as seen in FIG. 4. A bracketin the form of two spaced plates 37 is attached to the end of each arm34 opposite the stop 33, a pivot pin 38 extends between the plates 37and is attached to one end of a threaded rod 39, the other end of whichis received by a flange 41 provided on the related side wall 7. Nuts 42adjustably secure each rod 39 to the related flange 41, whereby the arms34 can be adjusted about the pivot shaft 24 so as to move the stops 33in the slots 35 thereby adjusting the torsion in the springs 28 and theinitial tension in the chains 17.

The arms 23 and pivot shaft 24 are vertically adjustably mounted withrespect to the related side walls 7 since the ends of the pivot shaft 24and the bushings 25 are carried by respective plates 43 secured by bolts40 to the side wall 7 with the bolts 40 disposed in slots 44 provided inthe side wall 7 to permit relative sliding movement of the plates 43.Each plate 43 is formed with a flange 45 to which is attached one end ofa threaded rod 46, with the other end of rod 46 adjustably attached tothe related side wall flange 41 by nuts 47. Adjustment of the nuts onrod 46 after loosening the bolts 40 either raises or lowers the plates43 relative to the side walls 7 so as to move the pivot shaft 24, andhence the arms 23, to a desired position.

After this adjustment, the pivot shaft 24 and the arms 23 coupledthereto are firmly held in the desired position by the nuts 47 and thethreaded rod 46, and also by the bolts 40 firmly tightened to the sidewalls 7. It will be noted that by this adjustment, the position of thesprockets 19 relative to fixed upper sprockets 49 of the rear expandablemember 9, when the baler is empty, can be changed. It will also be notedthat, as a bale is being formed in the bale chamber, the sprockets 19move upwardly and away from the fixed upper sprockets 49 of the rearexpandable member 9 by virtue of the arms 23 supporting the sprockets 19pivoting in a counter clockwise direction as seen in FIGS. 1 and 2. Thismovement of the sprockets 19 has been kept to an acceptable minimum bylocating the pivot shaft 24 substantially offset relative to the centerof the arms 23, so that the sprockets 19 are positioned closer to thepivot shaft 24 than the guide rollers 21. Using the adjustability of thepivot shaft 24 in a generally vertical direction, the front expandablemember 8 is set so that, in the empty condition of the baler, thesprockets 19 are positioned slightly lower than the fixed sprockets 49of the rear expandable member 9 and as close as possible to the forward,generally vertical inner course 70 of the rear expandable member 9without engaging the rear expandable member 9.

It will also be noted that, as a bale is being formed in the balechamber, the arms 23 pivot counterclockwise as seen in FIGS. 1 and 2,until the guide rollers 21 engage the inner and outer runs of theendless chains 17. At this moment, further pivoting of the arms 23 inthe counterclockwise direction, and further expansion of the innercourse 60 of the expandable member 8 becomes impossible with the innercourse 60 assuming a virtually fixed position which is very much thesame as the fixed position assumed by the bale forming means in the typeof baler with a fixed bale chamber.

The rear expandable member 9 comprises a pair of spaced endless chains48 located adjacent, but inset from, the respective side walls 7 andinterconnected by a plurality of slats 22, the construction of whichwill be described later. The slats 22 extend beyond the chains 48 andterminate just short of the side walls 7 as shown in FIG. 5. Each chain48 extends around an upper fixed sprocket 49, a lower fixed sprocket 51associated with the rotor 16, and movable guide rollers 52. The rollers52 are arranged in upper and lower pairs. When the machine is empty(FIG. 1), only one roller 52 of each pair is in engagement with thechains 48, but when a bale nears completion, both rollers 52 of eachpair are in engagement with the chains 48. Also, as a bale nearscompletion, both the inner and outer runs (as seen in FIG. 2) of thechains 48 engage the rollers 52. The rollers 52 of each pair arerotatably mounted on respective ends of a crosspiece 53 of a generallyT-shaped support, the stem 54 of which is provided with a pivot pin 55intermediate its ends. Each pivot pin 55 extends from the stem 54through an arcuate slot 56 in the associated side wall 7 and is attachedto a support arm 57 which is pivotally mounted at 58 on the side wall 7at the center of curvature of the slot 56. The end of each stem 54 ofthe T-shaped support remote from the crosspiece 53 is connected to oneend of a tension spring 59, with the other end of the spring 59 attachedto the associated side wall 7. The two upper crosspieces 53 and the twolower crosspieces 53 are interconnected by respective transverse tubularbeams 61 to ensure that the two upper and two lower T-shaped supportspivot in unison. The springs 59 serve in the empty condition of thebaler, to bias the upper T-shaped supports in a clockwise direction, andto bias the lower supports in a counter clockwise direction, as viewedin FIG. 1, whereby one roller 52 of each pair engages the associatedchain 48 to maintain tention therein and take up any slack in the chain48, resulting from wear. Also, the support arms 57 are pivoted in adirection towards the bale start chamber 11 until the pivot pins 55engage the forward ends of the arcuate slots 56. It will also be notedthat in this empty baler condition, the rear expandable member 9 assumesa generally rectangular configuration in side view with inner course 70defining the rear surface of the bale start chamber 11 and beingoriented generally vertically as seen in FIG. 1.

As a bale is being formed in the bale chamber, the inner course 70 ofthe rear expandable member 9 is moved rearward and expanded against theforce of the springs 59 between the top and bottom sprockets 49 and 51,respectively. As the bale nears completion, both guide rollers 52 ofeach pair first engage the outer runs of the respective chains 48 andultimately, the inner runs of the chains 48 also engage the guiderollers 52. Any stretching of the chains 48 resulting from wear iscompensated by the T-shaped supports moving generally radially outwardlyabout the pivot mountings 58, whereby the pivot pins 55 are moved awayfrom the inner ends of the slots 56.

It will be understood that, like the inner course 60 of the frontexpandable member 8, the course 70 of the rear expandable member 9 alsocannot expand any further once both the inner and outer runs of thechains 48 engage the guide rollers 52. Thus, the course 70 of the rearexpandable member 9 assumes a virtually fixed position such as the baleforming means in a fixed chamber baler.

Since the guide rollers 21,52 at times engage the opposed inner andouter runs of the respective associated chains 17,48, these guiderollers 21,52 must have smooth outer surfaces, instead of toothed outersurfaces, such as sprockets which would interfere with the propersimultaneous guidance of both runs of the chains.

Referring to FIGS. 6 to 8, it will be seen that the slats 22 formingpart of both the front and rear expandable members 8 and 9 are formedfrom tubular stock and, as already mentioned, extend essentially thefull width of the machine. The chains 17 and 48 are inset from the endsof the slats 22, as already described with reference to FIG. 5, in orderto reduce the unsupported central length of each slat and to lessen thechance of the slats flexing and being permanently deformed while a baleis being formed. Each slat 22 is flattened at each end with theflattened portion 62 extending from the end of the slat to just beyondthe point of connection to the chain 17 or 48. As best seen in FIG. 8,the flattened portion 62 of each end of each slat 22 comprises a flatbottom portion 63 and an opposed top portion having alongitudinally-extending central portion 64 extending parallel to, butspaced from, the bottom portion 63 and being flanked by two upstandingportions 65. Thus the top surface of each flattened slat portion 62 ischannel-shaped.

The flattening of the ends of the slats 22 destroys the inherentstrength of the previous tubular stock and in order to restore thisstrength, a fillet or insert 66 cut from flat metal strip is disposedinside each flattened portion 62 in the space between the bottom portion63 and the top central portion 64. Two longitudinally-spaced bores 67are formed through each flattened portion 62, as well as through theinsert 66, for the reception of bolts 68 by which the slat 22 isattached to lugs 69 carried on the associated chain 17, 48,with the lugs69 being provided with holes to receive the bolts 68. It will be notedfrom FIG. 8 that the upstanding portions 65 of the flattened endportions 62 extend above the heads of the bolts 68, whereby the bolts 68are protected from excessive abrasive wear by the crop material, and thelikelihood of crop material getting hooked around the bolt heads isreduced. It will also be noted that the upstanding portions 65 liegenerally within the outer periphery of the slat 22 as seen in FIG. 8.The threaded ends of the bolts 68 and the nuts 50 cooperating therewithare positioned on the sides of the chains 17,48 facing away from a balebeing formed. The chains 17,48 with the lugs 69 thereon are commerciallyavailable.

It will be understood that the front and rear surfaces of the startchamber 11 are defined respectively by the slats 22 on the inner runs ofthe chains 17 extending between the sprockets 18,19 and by the slats 22on the inner runs of the chains 48 extending between the upper and lowersprockets 49,51. These surfaces change shape as a bale is formed, beingtransformed from linear to arcuate as has already been mentioned and aswill be further described in more detail.

Referring to FIGS. 9 and 10, the combined crop feeder and bale supportdevice 15 comprises a hollow drum 71 having a smooth outer surface andprovided with two diametrically opposed rows of apertures 72 each ofwhich receives an insert 73 from within the drum 71 with the insert 73being bolted to the drum 71. Each insert 73 comprises two hemisphericalshells 74 formed with flanges 75 by which the insert 73 is bolted todrum 71. The sphere formed by the two shells 74 contains a bushing 76formed of elastomeric synthetic plastics material. Each shell 74 has anaperture 77 therethrough for a rod or finger 78 mounted in a radialextension 79 of a bushing 81 formed of elastomeric synthetic plasticsmaterial. Each rod 78 is retained in the extension 79 by a pin 82, andeach bushing 81 is rotatably mounted on a stationary crankshaft 83 theends of which are received in bearings 84 provided in end plates 85 ofthe drum 71. The drum 71 is driven and rotates around the crankshaft 83,whereby the rods 78 are alternately extended from the outer surface ofthe drum 71 adjacent the pick-up unit 14 and retracted into the drum 71adjacent the rotor 16 by sliding in and out of the apertures 77 andbushings 76, with the ends of the rods 78 describing the circleindicated at 80.

When the baler is empty, the combined crop feeder and bale supportdevice 15, together with the courses 60,70 of the expandable members 8,9define the generally wedge-shaped bale start chamber 11 with the device15 being located at a distance beneath the lower end of the frontexpandable member 8 to form a bale chamber inlet opening. The device 15is mounted proximate, but forwardly of the rotor 16 so that, in theempty condition of the baler, the generally vertical course 70 of therear expandable member 9 is rearward of the device 15. The device 15 inpart forms the bottom of the bale start chamber 11.

The device 15 is positioned relative to the lower sprockets 18 of thefront expandable member 8 and the rotor 16 (which is part of the rearexpandable member 9) so that, as a bale is nearing completion within thebale chamber, the bale is supported at least in part by the drum 71 ofthe device 15. Hence the drum 71 is positioned, together with othercomponents of the machine on a circumference defining the cylindricalbale chamber shape 11', However, the device 15 is also positionedrelative to the cylindrical bale chamber shape 11' so that, as a bale isbeing formed in the bale chamber its center of gravity is moved from aposition located generally above the device 15 to a position locatedrearward of the device 15.

The fingers 78 are substantially in their retracted position at thepoint on the drum 71 where a bale is supported by the drum 71, therebyavoiding the fingers 78 penetrating into the bale and adverselyaffecting the surface thereof. The fingers 78 are fully extended at theside of the drum 71, facing the pick-up unit 14 in order to take overcrop material therefrom.

Referring to FIGS. 11 and 12, the rotor 16 will now be described. Thefunction of the rotor 16 is to help support a bale during formationwithout imparting any substantial vibration to the bale which mightimpair the formation thereof or cause unacceptable wear and damage tothe machine. As already described, the chains 48 extend around sprockets51 associated with the rotor 16 and if the rotor 16 were not provided,the slats 22 of the rear expandable member 9 would continuously impactwith the bale being formed, in a manner that would attempt to raise thebale on each occasion of impact and thus subject the bale to vibrationin a generally vertical direction. The rotor 16 overcomes this problemby providing pockets for the slats 22 to enter before and as they impactthe bale, whereby the rotor 16 together with the slats 22 received inthe pockets thereof, provide a substantially smooth or continuoussurface on which the bale is supported.

The rotor 16 comprises a hollow tubular core 86 extending between thetwo sprockets 51 and closed at each end by a plate 87 formed with atubular extension 88 of reduced diameter concentric with the core 86,and formed with an annular recess 89 around its outer end. The recess 89receives one end of a tube 91 having the same outer diameter as theextension 88 and being closed at its outer end by an end plate 92 whichis bolted to a flange 93 carried by a stub shaft 94 by which the rotor16 is mounted for rotation in bearings (not shown) provided in therespective side walls 7. Each tube 91 is surrounded along the majorityof its length by a further tube of the same outer diameter as the core86 and representing an extension 86' of core 86. Each core extension 86'is supported by two annular end plates 95 carried by the tube 91.

On the main core 86 and the two core extension 86' of the rotor 16 thereare mounted respective outer rotor surface members 96 and 96', which aregenerally star-shaped in cross-section as seen in FIG. 11, thusproviding four longitudinally extending pockets 97 for the reception ofthe slats 22 associated with the chains 48. The surface members96,96'are each formed from four identically shaped sections of sheetmetal which are welded together at the four points of the star shape andwhich are welded to the respective end plates 87,95 of the rotor 16.

The two sprockets 51 associated with the rotor 16 are each welded to anannular disc 99 attached to the tube 91. On assembly, the tubes 91 areslid into the recesses 89 in the extension 88 and the sprockets 51 arebolted to respective discs 98 secured to the extensions 88 via bolts 90which are welded to the sprockets 51. Thus the sprockets 51 are insetfrom the outer ends of the rotor 16 to engage the chains 48.

As the rotor 16 rotates, the slats 22 move into the pockets 97 as thechains 48 pass around the sprockets 51, whereby a substantiallycontinuous support surface is contacted by the bale being formed. Inthis respect, it will be seen from FIG. 11 that when a slat 22 isreceived in a pocket 97, the outer surface of the slat 22 is located onthe circle 101 circumscribed by the outer points of the surface members96,96' of the rotor 16.

From FIG. 2, it will be undertood that only part of the weight of a balebeing formed in the bale chamber is supported on the rotor 16 withanother part of the bale weight being supported, as already mentioned,by the combined feeder and bale support device 15.

It should be noted that the number of teeth on each sprocket 51 is Ntimes the number of links in the chains 48 between adjacent slats 22,where N is an integer, although preferably not one. Also, the number ofteeth on each sprocket 51 is a multiple of the number of pockets 97provided in the rotor 16. It will be seen from FIG. 11 that in the firstembodiment, each sprocket 51 has sixteen teeth which is a multiple ofthe four pockets 97 and which makes N=4 since a slat 22 is attached toevery fourth link of the chains 48.

The drives for the various driven components of the baler are shown inFIG. 2 of the drawings, having been omitted from FIG. 1 for clarity. Asprocket 102 on the output shaft 103 of the gearbox 6 drives, via achain 100, one sprocket of a triple sprocket 104 mounted on a shaft 105on which the sprocket 18 of the front expandable member 8 is mounted,whereby the chains 17 are driven in a clockwise direction as seen inFIGS. 1 and 2. Both chains 17 are driven since the shaft 105 is commonto both sprockets 18. A further chain 106 extends around a secondsprocket of the triple sprocket 104 and around a sprocket 107 mounted ona common shaft 108 for the two sprockets 49 of the rear expandablemember 9, whereby the two chains 48 are also driven in a clockwisedirection as seen in FIGS. 1 and 2. Thus the inner runs of the chains 17and 48 partially defining the bale start chamber 11 move in generallyopposite directions so as to impart a rolling motion to the cropmaterial fed to the bale start chamber 11.

A chain 109 extends around the third sprocket of the triple sprocket 104and around a sprocket 111 provided on one end of the drum 71 of thedevice 15, whereby the device 15 is driven in a clockwise direction asseen in FIGS. 1 and 2. A pulley 112 is also coupled to the sprocket 111and a belt 113 extends from pulley 112 to a pulley 114 on the pick-upunit 14 so as to drive the pick-up unit 14 also in a clockwise directionas seen in FIGS. 1 and 2.

In operation of the embodiment of FIGS. 1 to 12, the machine is hitchedto the tractor or other towing vehicle via the drawbar 3, with the driveshaft 4 connected to the tractor PTO so that the chains 17,48, thedevice 15 and the pick-up unit 14 are driven as described above. Thus asthe machine is towed across a field of previously cut material, pick-upunit 14 picks up crop material and conveys it rearwardly toward thedevice 15. The fingers 78 of the device 15 take over the crop materialand feed it through the inlet opening of the start chamber 11 and intoengagement with the course 70 of the rear expandable member 9. It willbe understood from the foregoing description that the slats 22 of therear expandable member 9 are relatively closely spaced, and thereforeserve to carry the crop material upwardly into the start chamber 11where the crop tumbles and falls downwardly, assisted by the slats 22 ofthe generally downwardly moving course 60 of the front expandable member8. The relatively gentle tumbling action of the crop material results ina generally soft core for the bale being formed. However, the rollingaction imparted to the crop material by the device 15, and the slats 22of the courses 60,70 of the expandable members 8,9 results in a smallercore than in a conventional fixed chamber baler. Experience has shownthat the core usually starts to roll at a location above the device 15and inbetween the courses 60,70 of the expandable members 8,9. As thesize of the bale core increases, the start chamber 11 becomes full,whereupon the core presses increasingly harder on the slats 22 of thecourses 60,70 of the expandable members 8,9 with the result that thecourse 60 of the expandable member 8 is urged to the left as seen inFIG. 1, and the course 70 of the expandable member 9 is urged to theright, the courses 60 and 70 being urged against the action of thesprings 28 and 59, respectively. Accordingly, the layers of cropmaterial surrounding the soft core begin to be more consolidated, andthe density of the bale increases to the outer shell thereof since thesprings 28 and 59 progressively increase the tension in the chains 17,48of the expandable members 8,9. It will be understood that the degree ofbale compaction depends on the forces exerted by the springs 28 and 59.With the illustrated arrangement it is easy and convenient to vary thesespring forces and thus vary the density of the bale.

It should be noted that as the courses 60,70 of the expandable members8,9 are expanded as the bale increases in size, they form complementaryportions as seen in FIG. 2 of the cylindrical bale chamber shape 11'. Asalready mentioned, this expansion is accompanied by pivotal movement ofthe arms 23 and the T-shaped supports 53,54 to the positions indicatedin FIG. 2. It should also be noted that the arms 23 are pivoted offcenter in order to minimize the size of the gap between the sprockets 19and the sprockets 49 through which crop material may be lost.

When the arms 23 and the T-shaped supports 53,54 are in the positions ofFIG. 2, the inner and outer runs of the chains 17 are in contact withthe sprockets 18 and 19 and the rollers 21, whereby the chains 17 arepositively supported in fixed positions with no slack therein. Likewisethe chains 48 are positively supported in fixed positions by thesprockets 49,51 and the rollers 52. Thus when the bale size 13 of FIG. 2is reached the slats 22 of the courses 60,70 of the expandable members8,9 are moved along a fixed path around the bale being completed. Asmore crop material is fed into the bale chamber and since the balechamber cannot expand any further, a hard shell or outer layer is formedon the bale with compaction taking place in an inward direction from theoutside. The hardness of this outer shell, and hence its weatheringcharacteristics, depends on the amount of crop material fed into thebale chamber after the bale has reached its maximum diameter. This iscomparable to the hard shell which can be produced with conventionalfixed chamber balers.

As the bale is nearing completion in the bale chamber, it is supportedin part on the drum 71 of the device 15 and on the rotor 16, togetherwith the slats 22 of the rear expandable member 9 as they enter thesuccessive pockets 97 of the rotor 16. This occurs without any unduevibration to the bale in the bale chamber. It will also be understoodmainly from FIG. 2, that the front expandable member 8, together withthe sprockets 18, and the rear expandable member 9, together with thelower pairs of guide rollers 52 on the lower T-shaped supports 53,54,also assist in supporting the weight of the bale in the bale chamber.

As already mentioned, the particular mounting of the T-shaped supports53,54 provides compensation for any stretching of the chains 48 of theexpandable member 9 as a result of wear. When the bale 13 has beencompleted, the tailgate 12 is raised (by means not shown) about theshaft 108 and since the center of gravity of the bale 13 lies within therear portion of the bale chamber shape 11', there is a natural tendencyfor it to roll from the machine on the raising of the tailgate 12. Thistendency is augmented by the action of the device 15, which continues tobe driven, and thus positive discharge of a completed bale is achieved.

As soon as a completed bale 13 is discharged from the machine, thesprings 28 and 59 return the arms 23 and T-shaped supports 53,54,respectively, to the positions of FIG. 1, whereby the start chamber 11is re-formed ready for forming the next bale. It will be understood thatthe machine is capable of forming bales of less than the maximumdiameter since bale discharge can be effected at any time by raising thetailgate 12. While any bale less than the maximum size will not have theheavily compacted outer layer or shell, such a bale will hold togetherif the springs 28,59 have been set to give more density to the balebeing formed.

Turning now to FIG. 13, there is shown a modified arrangement of theguide means for guiding the chains 48 when a bale has reached itsmaximum diameter in the bale chamber. FIG. 13 shows one T-shaped support53,54 in the position attained when a competed bale has been formed. Inthis arrangement, each T-shaped support 53,54 is provided with twosprockets 115, one in engagement with the inner run of the associatedchain 48 at a location proximate one guide roller 52 and the other inengagement with the outer run thereof at a location proximate to theother guide roller 52. The inner and outer runs of the chains 48 engagethe rollers 52 when in the position (bale commplete) of FIG. 13. Thisarrangement improves the guidance of both runs of the chains 48 on theguide rollers 52 when a bale has reached its maximum size within thebale chamber by positively holding the chains 48 in alignment with therollers 52.

FIGS. 14 and 15 show an alternative embodiment of round baler which issimilar to that of FIGS. 1 to 12, the differences being in respect tothe chain tensioning devices associated with the front and rearexpandable members 8 and 9. In this embodiment the arms 23 are replacedby arms 116 which carry at one end the guide rollers 21, with thesprockets 18,19 being fixed to the frame 1. Each arm 116 is pivotedintermediate its ends on a pivot pin 117, with the other end of the arm116 connected to one end of a tension spring 118 which is attached atits other end to the frame 1. With this arrangement, the gap between thesprockets 19 of the front expandable member 8 and the sprockets 49 ofthe rear expandable member 9 remain constant and small so that any lossof crop material therethrough is small. In the embodiment of FIGS. 1 to12, the sprockets 19 are movable relative to the sprockets 49 as a baleis formed.

In regard to the rear expandable member 9, the lower T-shaped supports53,54 are replaced by arms 119 which carry the guide rollers 52, withthe arms 119 being mounted for limited movement relative to the sidewalls 7 by virtue of a pair of elongated slots 121 formed in the sidewalls 7 which slidably receive mounting pins 122 attached to theassociated arms 119. This particular mounting, like the position of thesupport arms 57 in the embodiment of FIGS. 1 to 12, providescompensation for any stretching of the chains 48 as a result of wear.The upper T-shaped supports 53,54 are replaced by arms 123 which carrythe rollers 52 and are each centrally pivoted on one end of a furtherarm 124 which is pivoted at its other end to the frame 1. One end of acable 125 is attached to each arm 124 intermediate its ends, the otherend of the cable 125 being secured to one end of a tension spring 126which in turn has its other end attached to the frame 1, the cable 125passing over a pulley 127 on an extension 128 on the frame 1. Thus asthe course 70 of the expandable member 9 expands as the bale grows (asalready described with respect to the first embodiment), each arm 124 ispulled counterclockwise about its pivot and takes with it the cable 125which streches the spring 126 associated therewith, thereby increasingthe tension in the chains 48 of the expandable member 9. Similarly, thesprings 118 increase the tension in the chains 17 of the expandablemember 8 as the arms 116 are pivoted counterclockwise and stretch thesprings 118. It will be noted that, unlike the embodiment of FIGS. 1 to12, both guide rollers 52 of each pair of guide rollers engage the outerrun of the respective chains 48, when the baler is empty. In all otherrespects, the operation of the embodiment of FIGS. 14 and 15 is similarto that described for the embodiment of FIGS. 1 to 12.

It will be seen that the present invention provides a round baler whichcan produce bales with a hard outer shell while the density of the cropmaterial elsewhere within the bale can be varied greatly from a lowdensity comparable to bales produced with conventional fixed chamberbalers to a high density comparable to bales produced with conventionalexpanding chamber balers, thus combining advantages of conventionalfixed and expanding chamber balers.

As already mentioned, the device 15 has a dual function in feeding cropmaterial to the bale chamber from the pickup unit 14, and in helping tosupport the bale as it is being completed. The device 15 thus performsan important function in the formation of a bale and without itspresence, the pickup unit 14 would have to be mounted much closer to theinlet opening of the bale chamber.

The function of the rotor 16 is also important in lending furthersupport to each bale as it is formed and in so doing to present, inconjunction with the slats 22 a substantially smooth surface to thebale. To this end, the pockets 97 are formed in the surface of the rotor16 to accommodate the slats 22 as they pass therearound. As alreadyexplained, this prevents the slats 22 from imparting vibrations to thebale being formed which would impair formation.

Alternatively, the expandable members 8,9 may be augmented by one ormore fixed bale forming means. Also, the chain and slat type members 8,9may be replaced by the well known belt type bale forming members.

The present invention provides a round baler capable of producing a balewith a hard outer shell, and with either a relatively high density or arather low density of crop material elsewhere within the bale. Themachine can produce a maximum sized bale in approximately two minutes,provided crop material is fed to the bale chamber at the appropriterate. Of this bale forming time, between 1/3 and 1/4 is devoted toforming the hard outer shell. This is a very important aspect because itprovides the possibility of producing with a baler of the type having anexpanding bale chamber, bales with a hard outer shell, such as isobtained with known balers of the type having a fixed chamber. It willbe understood that the tension initially set in the chains 17,48 of theexpandable members 8,9 determines the hardness of the bale core, as wellas influencing the overall density of the bale except for the hardnessof the outer shell which basically is determined by the amount of cropmaterial fed into the bale chamber after the bale chamber has expandedto its maximum diameter. In general, a baler in accordance with thepresent invention forms a bale core which is considerably smaller thanthat provided by known fixed chamber balers due to the positive rollingaction imparted to the bale. Thus, the baler produces a highlysatisfactory bale having qualities of both soft core and hard core baleswithout the baler being of complicated mechanical construction.

Having thus described the invention, what is claimed is:
 1. A roundbaler comprising:(a) a base frame; (b) side walls attached to said baseframe; (c) first and second expandable members arranged to definetogether with said side walls an initial generally vertically orientedwedge-shaped start chamber which expands to a generally cylindricalshape during bale formation; (d) an arm supporting said first expandablemember, said arm being pivotally mounted on at least one of said sidewalls and carrying guide members at the ends thereof around which saidfirst expandable member passes; and (e) upper and lower T-shapedsupports supporting said second expandable member, each said T-shapedsupport being pivotally mounted on at least one of said side walls andcarrying a pair of guide members for engaging said second expandablemember.
 2. The round baler of claim 1, wherein said arm is normallyurged in a direction to maintain tension in said first expandablemember, and said T-shaped supports are normally urged in oppositedirections relative to each other to maintain tension in said secondexpandable member.
 3. The round baler of claim 2, wherein said arm ispivotally mounted on said at least one side wall intermediate the endsof said arm but offset from the center of said arm.
 4. The round balerof claim 2, wherein the position of said arm is adjustable verticallywith respect to said side walls.
 5. The round baler of claim 4, furthercomprising a pivot shaft connected to said arm, a plate carrying saidpivot shaft, said plate being secured to one of said side walls butbeing movable upwardly and downwardly relative to said one side wall tovertically adjust the position of said arm.
 6. The round baler of claim2, wherein each said T-shaped support includes a stem pivotally mountedto one end of a support arm which is pivotally attached to one of saidside walls.
 7. The round baler of claim 6, wherein said stem of eachsaid T-shaped support is pivotally mounted to said support arm by apivot pin which extends through a slot formed in said one side wall. 8.The round baler of claim 7, wherein each said T-shaped support alsoincludes a cross piece carrying said pair of guide members.
 9. The roundbaler of claim 7, further comprising springs normally urging saidT-shaped supports in said opposite directions until each said pivot pinengages one end of the associated said slot.
 10. The round baler ofclaim 2, wherein said T-shaped supports are normally urged in saidopposite directions so that only one guide member of said pair of guidemembers on each said T-shaped support engages said second expandablemember when said start chamber is empty.
 11. In a round baler having abase frame, side walls attached to said base frame, first and secondexpandable members arranged to define together with said sidewalls aninitial generally vertically oriented wedge-shaped start chamber whichexpands to a generally cylindrical shape during bale formation, theimprovement comprising:(a) an arm supporting said first expandablemember, said arm being pivotally mounted on at least one of said sidewalls and carrying guide members at the ends thereof around which saidfirst expandable member passes; and (b) upper and lower T-shapedsupports supporting said second expandable member, each said T-shapedsupport being pivotally mounted on at least one of said side walls andcarrying a pair of guide members for engaging said second expandablemember.